Table 1.
Demographic characteristics of the cognitively normal population and time dependent healthy lifestyle groups at baseline. Data are number (%), unless otherwise specified
| Demographic characteristics | Total (n=29 072) | Healthy lifestyle groups | |||||
|---|---|---|---|---|---|---|---|
| Unfavourable group (n=6967) | Average group (n=16 549) | Favourable group (n=5556) | |||||
| Female | 14 113 (48.54) | 3402 (48.83) | 7995 (48.31) | 2716 (48.88) | |||
| Mean (SD) age (years) | 72.23 (6.61) | 72.90 (6.74) | 72.30 (6.64) | 71.16 (6.22) | |||
| Place of residence: | |||||||
| Rural | 13742 (47.27) | 3263 (46.84) | 7812 (47.21) | 2667 (48.00) | |||
| Urban | 15 330 (52.73) | 3704 (53.16) | 8737 (52.79) | 2889 (52.00) | |||
| Region: | |||||||
| North | 8670 (29.82) | 2000 (28.71) | 4983 (30.11) | 1687 (30.36) | |||
| West | 9585 (32.97) | 2274 (32.64) | 5469 (33.05) | 1842 (33.15) | |||
| South | 10 817 (37.21) | 2693 (38.65) | 6097 (36.84) | 2027 (36.48) | |||
| Marital status: | |||||||
| Widowed | 2593 (8.92) | 595 (8.54) | 1483 (8.96) | 515 (9.27) | |||
| Divorced, separated, or single | 3670 (12.62) | 889 (12.76) | 2048 (12.38) | 733 (13.19) | |||
| Married | 22 809 (78.46) | 5483 (78.70) | 13 018 (78.66) | 4308 (77.54) | |||
| Years of education: | |||||||
| <1 | 4242 (14.59) | 1042 (14.96) | 2356 (14.24) | 844 (15.19) | |||
| 1-6 | 9618 (33.08) | 2286 (32.81) | 5593 (33.80) | 1739 (31.30) | |||
| 7-12 | 12 182 (41.90) | 2904 (41.68) | 6922 (41.83) | 2356 (42.40) | |||
| >12 | 3030 (10.42) | 735 (10.55) | 1678 (10.14) | 617 (11.11) | |||
| Monthly household income (Chinese Yuan): | |||||||
| 1000-2999 | 2208 (7.59) | 502 (7.21) | 1272 (7.69) | 434 (7.81) | |||
| 3000-4999 | 8715 (29.98) | 2132 (30.60) | 4872 (29.44) | 1711 (30.80) | |||
| 5000-10 000 | 17 369 (59.74) | 4147 (59.52) | 9964 (60.21) | 3258 (58.64) | |||
| >10 000 | 780 (2.68) | 186 (2.67) | 441 (2.66) | 153 (2.75) | |||
| Occupation: | |||||||
| Manual labourer | 12 271 (42.21) | 3026 (43.43) | 6922 (41.83) | 2323 (41.81) | |||
| Office worker | 9076 (31.22) | 2107 (30.24) | 5226 (31.58) | 1743 (31.37) | |||
| Household | 4913 (16.90) | 1146 (16.45) | 2809 (16.97) | 958 (17.24) | |||
| Others | 2812 (9.67) | 688 (9.88) | 1592 (9.62) | 532 (9.58) | |||
| Mean (SD) BMI | 23.30 (4.08) | 23.20 (4.07) | 23.31 (4.08) | 23.36 (4.07) | |||
| Mean (SD) MMSE score | 27.52 (1.30) | 27.51 (1.29) | 27.52 (1.30) | 27.56 (1.31) | |||
| Medical illnesses: | |||||||
| Hypertension | 11 042 (37.98) | 2513 (36.07) | 6323 (38.21) | 2206 (39.70) | |||
| Diabetes | 5823 (20.03) | 1386 (19.89) | 3361 (20.31) | 1076 (19.37) | |||
| Hyperlipidaemia | 7842 (26.97) | 1987 (28.52) | 4463 (26.97) | 1392 (25.05) | |||
| Heart attack | 1913 (6.58) | 448 (6.43) | 1112 (6.72) | 353 (6.35) | |||
| Head injury | 1586 (5.46) | 376 (5.40) | 886 (5.35) | 324 (5.83) | |||
| Depression | 1740 (5.99) | 401 (5.76) | 984 (5.95) | 355 (6.39) | |||
| Cerebrovascular disease | 3018 (10.38) | 765 (10.98) | 1679 (10.15) | 574 (10.33) | |||
| Healthy lifestyle factors: | |||||||
| Never or former smoking | 23 206 (79.82) | 3795 (54.47) | 14 139 (85.44) | 5272 (94.89) | |||
| Never drinking | 11 505 (39.57) | 740 (10.62) | 6998 (42.29) | 3767 (67.80) | |||
| Active cognitive activity | 7151 (24.60) | 120 (1.72) | 3558 (21.50) | 3473 (62.51) | |||
| Regular physical exercise | 6776 (23.31) | 112 (1.61) | 3395 (20.51) | 3269 (58.84) | |||
| Active social contact | 6936 (23.86) | 104 (1.49) | 3542 (21.40) | 3290 (59.22) | |||
| Healthy diet | 14 304 (49.20) | 1001 (14.37) | 8887 (53.70) | 4416 (79.48) | |||
| Number of healthy lifestyle factors: | |||||||
| 0 | 1095 (3.77) | — | — | — | |||
| 1 | 5872 (20.20) | — | — | — | |||
| 2 | 9128 (31.40) | — | — | — | |||
| 3 | 7421 (25.53) | — | — | — | |||
| 4 | 4293 (14.77) | — | — | — | |||
| 5-6 | 1263 (4.34) | — | — | — | |||
| APOE ε4 carriers | 5939 (20.43) | 1602 (22.99) | 3373 (20.38) | 964 (17.35) | |||
| Mean (SD) follow-up period (years) | 6.65 (2.28) | 6.29 (2.15) | 6.60 (2.28) | 7.24 (2.30) | |||
A healthy diet is defined as adherence to the appropriate amounts of at least 7 of the 12 dietary components. Regular physical exercise is defined as spending at least 150 min/week of moderate exercise or 75 min/week of vigorous physical activity. Active cognitive activity is defined as participating in cognitive activities (including writing, reading, playing cards, mah-jong, and gaming) at least twice per week. Active social contact is defined as participating in social activities (including attending meetings or parties, visiting friends or relatives, travelling, and chatting online) at least twice per week. Never drinking and never or former smoking were also regarded as healthy factors. Age, BMI, medical illnesses (including hypertension, hyperlipidaemia, heart attack, cerebrovascular disease, head injury, diabetes, and depression), lifestyle factors (including smoking status, alcohol consumption, diet, physical exercise, cognitive activity, and social contact), and neuropsychological assessments were time-dependent variables. Other demographic information (including sex, place of residence, region, marital status, years of education, monthly household income, and occupation) and the APOE genotype were assessed at baseline only. SD=standard deviation; BMI=body mass index; MMSE=Mini Mental State Examination; APOE=apolipoprotein E.